I haven't seen any at all yet.

One white, and two different sized red ones now.

What's so flaming annoying is that, after six years, the local pain-in-the-derriere heron has discovered my pond and I now have to keep it netted. The two red ones were under the netting, so I presume they've hatched out this year. Luckily I was able to set them free. I think it's really sad that I have to do this, but I'm not going to take the chance of losing my fish. Incidentally, I was once told that herons eat frogs. According to my RPSB bird book they also eat small mammals, so maybe that accounts for the decline in my frog population? If I catch the blooming thing, I'll take it on a long trip somewhere and dump it where it can't find its way back.

Yes. they definitely eat frogs and newts. That's why the only time of yar they come to my ponds is frog breeding time.
If you rig up a framework of bamboos with string strung around them, you can lay / tie the net over that, leaving a gap for wildlife to get in and out.

Thanks for info, Damp.

I had my thinking cap on some days ago and I'm lucky that I have a couple of bushes near the pond that I can use to tie my netting to, along with a bamboo pole, leaving it free for the birds and other wildlife to come and go safely underneath.

Wilkinson's sell two types of pond/garden netting, one of which is very fine and isn't very visible over the pond. I would NEVER use this, the wider variety, or the usual green garden netting in my garden because I had a very upsetting experience years ago when a poor blackbird got caught up in it and died. Considering how I look after all my birds and creatures in the garden, I was absolutely mortified and decided to never to use it again. I now use either narrow gauge chicken wire or those mini plastic tunnels sold for veg rows.